1. Field of the Invention
The present invention relates to an image forming apparatus and a document size determination method thereof. More particularly, the present invention relates to a document size determination device for an image forming apparatus and a document size determination method thereof capable of determining the size of a document fed by an automatic document feeder and feeding a sheet of copy paper of a size corresponding to the document.
2. Description of the Related Art
In a conventional image-forming apparatus such as a scanner, a facsimile machine, a photocopier, and so on, a user has to set documents sheet by sheet to read out images of the documents. The user also has to input the sizes of the set documents one by one.
However, with the automatic document feeder installed, a large image-forming apparatus can automatically read out plural documents at a time. The automatic document feeder can automatically feed and set documents to a position for reading out images so as to enable the image-forming apparatus to read out document images, when a user loads a plurality of documents onto a document feeder tray at one time.
That is, when the automatic document feeder is used, the plurality of loaded documents are picked up one by one, and fed along a document transfer path, so that the image of the fed document is by the image-forming apparatus, and then transferred to a document outlet. Therefore, the plurality of documents can be automatically read out without manipulation by the users when the automatic document feeder is used.
Thus, even when a user wants to have plural documents read out, the user does not have to set the documents one by one since the documents are to be automatically and conveniently read out. However, the automatic document feeder has a problem when the sizes of plurality of documents are different.
That is, as a user sets two or more sizes of documents into an image-forming apparatus, the image-forming apparatus supplies a sheet of paper based on the size of a document read out for the first time, and then reads the image of the document, so that a next document fed in after and possibly larger in size than the first read-out document is only partially read out causing the image of the document to be partially cut off.
Further, when a document to be read out next time is smaller in size than the document read out for the first time, the next document is copied on a sheet of paper larger in size, which wastes paper as well as forms an image having a blank space that the user does not want.
Furthermore, even if the next document has the same size as the first document, the same problem occurs when documents are loaded onto the automatic document feeder in a different orientation from the first document, that is, in a portrait or a landscape orientation different from the first document.
Accordingly, in the case of reading out documents of two or more sizes loaded onto the document tray of the automatic document feeder, there exists a problem in that a user can read out the documents only after sorting the documents by size and setting only the documents having the same size on the document tray. Then, the user has to reset the image forming apparatus for different documents in size since the different sized documents can not be set at one time.